(1) Field of the Invention
This invention relates to an item input device for inputting multiple item information into an information processing system by a keying operation, and more particularly to a roll type item input device wherein a plurality of page sheets containing input information is rolled about a shaft and the desired page sheet is selected by rotating the shaft.
(2) Description of the Prior Art
An item input device of this type usually employs a page drum formed by directly fixing one end of a plurality of plastic page sheets to the circumferential surface of a rotating shaft. The page drum is accommodated in the main device body to insure free insertion and withdrawal and thus to provide easy exchange of each page sheet.
When an operator operates the desired page selection key of the keyboard, said rotating shaft automatically rotates a specified angle in the direction opposite to the page sheet winding direction, thereby bringing about the "setting" condition wherein the free end of the desired page sheet is placed at the page sheet guide exit. Subsequently, said rotating shaft automatically rotates in the same direction as the page sheet winding direction, guiding the desired page sheet along the lower side of the input keys of the keyboard. Thus, the input keys of the keyboard are given functional displays in accordance with the input information of the page sheet. When an operator operates the desired input keys by referring to the functional display under this condition, the key signal generated by said input key, the page sheet identification signal generated by the page selection key, and the page drum identification signal indicating the kind of drum built in, are input to the data processing system as input information.
The system known in the art has a plurality of page drums previously prepared, each having different input information provided thereon in order to input many pieces of information. Each page drum is built into the main body as explained above in order to ensure the exchange of each page drum. However, page drum replacement has been very troublesome up until now because such replacement has been performed manually by opening the keyboard and cover of the main body. In addition, the existing page drum employs a cartridge type structure having four rotating shafts for extending an endless bolt to hold the page sheet in the winding direction and in its accommodation cabinet, in addition to the rotating shaft and page sheets, thus making replacement troublesome due to heavy weight and large size. In addition, storing requires a wide space. In existing device, page selection is carried out by rotating the rotating shaft to wind the page sheets in the winding direction or reverse direction. Such an operation results in slack in those page sheets being wound around the rotating shaft other than the page sheets selected at the time of page selection. Resultingly, when page selecting operation is repeated several times, the arrangement of a page sheet at the time of winding is irregular, and mis-selection may occur. Such mis-selection increases as the page selecting operation speed increases.